Eldest Imouto
by Ssjshadic
Summary: Tanjiro-nii is incorrigible. Even as an official Demon Slayer, he cannot stop himself from being an older brother. Then again, even as a demon, Nezuko is no different. She can no more stop being the eldest daughter than he can stop being the eldest son. Just short glimpses into Nezuko's perspective over the course of Tanjiro's journey.
1. Chapter 1

A/N: Please accept this, an addition to the fairly young fandom of Demon Slayer. *Bows*

* * *

Waking up the first time _hurts_.

Pain grips her, spreads like fire outward from her stomach, all-consuming.

She writhes and howls and hits something. She barely registers the long fall. The agony in her gut is too sharp to ignore, too poignant to pay attention to anything else. Except…

A scent slithers through the pain. She can't see straight, can barely concentrate on listening, there is only that alluring scent. It beckons her, calls to her, the smell of _blood _and _flesh_. The tantalizing promise of making the ache stop overwhelms any other thought or instinct she has.

_Hungry_.

She lunges, growling, all claws and teeth and primal _need_. A buzzing sounds in her ears, but she cannot focus on it.

_Hungry_.

She finds purchase, clutches and pushes down her prey. Yet she meets resistance. Frustrated, she clenches her jaw around a stick her prey uses to protect itself- she must be stronger- bigger! She grows, and the ache _worsens_, a black hole carving itself out in her stomach. She struggles, presses harder, the promise of eating too much, she's so close to-

The buzzing clears up, grows louder.

"-ko! Nezuko!"

A name breaks through her hunger-driven frenzy, a single cushion against the agonizing ache. Her…

_Her _name.

_'I, Nezuko.'_

"Please, fight!"

The voice begs her. Her prey sounds afraid, but not for himself. For her.

With immense will, she forces herself to concentrate, _forces _her vision to clear, to bring the human garbed in green beneath her into focus.

Blood, pain not her own, an ache that makes her sick and sad instead of hungry flashes through her mind.

_'Tanjiro-nii.'_

Nezuko cries. For her family or for what she tried to do to her brother, she doesn't know.

A shift in the wind. A rustling sound brings a new scent, one she immediately labels a threat. A hand touches her neck, but she recognizes warmth, and kindness, and Tanjiro-nii, so she does not resist. They roll in the snow, something catches his hair.

They come to a rough stop with him still holding her.

Nezuko shrinks. The pain softens a little, but the scent of steel- of danger- lingers in the air, nearby. She's still confused, memories of her family- her brothers and sister, her mother- flashing through her mind. She can barely see straight. Focusing through the pain and the hunger is _hard_.

She only has Tanjiro-nii to ground her.

Another buzzing sound- another human speaking- reaches her, though words are indistinct. The voice, the one she assigns to the threat she still hasn't named, is _nothing _like her brothers- all sharp edge and cold. She wriggles in Tanjiro-nii's arms, trying to orient herself and assess the danger. Confusion drives her to restlessness more than acute fear of Steel. She dares not struggle too hard, though, or else she could hurt her brother.

Steel _moves_, and Tanjiro-nii's warmth vanishes from her side. Without it, she feels even more lost, and she growls, trying to wrench her arms free. When did she get caught?

Steel's scent is at her neck, and she snarls. She can't hear her brother anymore, too occupied with _death_ at her _throat_. A moment, and it's taken away, though nowhere near far enough for comfort.

She hears Tanjiro-nii's voice, screaming, pleading for a second before

_Pain_.

Sharp, immediate and cold like death and oblivion in her side.

She whines, vision blurry with the growing ache for relief, for _blood._

Tanjiro-nii shouts again, and the sword in her retracts. She sees her brother rushing toward her once her vision clears, green topped with brown and violet eyes barreling straight toward the threat, shoulder first.

He's struck, and he falls into the snow. He doesn't move.

_'No!'_

Anger floods through her, burning in her lungs and throat. It is a wild fire next to the smoldering hunger she feels, and her wound is forgotten.

She twists in her captors grip and _strikes_, kicks him away from her, away from her brother.

She has to protect Tanjiro-nii. She only _has _Tanjiro-nii.

He will not be taken from her.

Nezuko lunges for his prone form, clawed hand reaching out for his head. She moves to cover him, to guard him-

She remembers Rokuta, sees a glimpse of her baby brother beneath her, feels the phantom of pain she felt when she was impaled _with _him…

Her body did not protect him. It won't protect Tanjiro-nii.

She skids to a stop in front of him instead, arms out, snarling.

_'Stay away!'_

Nezuko charges. She swipes with her claws, throws punches and kicks with a reckless abandon, a fury that lets her ignore her own needs. Anything she can to keep the threat away from Tanjiro-nii.

Faster than she can react, a hand chops at her neck, and she falls asleep again.


	2. Chapter 2

A/N: Please accept this, another peek into the perspective of one demon Nezuko. *Bows*

* * *

Waking up the second time is easier.

Thinking comes a little more readily, though it is still like wading through thick, muddy water.

Immediately more important, though, there are no threats and the danger of Steel has left. Time has blunted her hunger, now less of a sharp knife and more of a steady gnaw. Something's been put in her mouth- the word bamboo flickers and vanishes- making eating impossible anyway.

She also wakes to Tanjiro-nii's hand holding hers, making the pain that much easier to bear. He rubs melted snow over her face with his other hand, rinsing off dried blood. She blinks at him when he pauses and looks at her. His lips tick upward on one side, but he doesn't speak.

Tanjiro-nii keeps her hand in his until they reach the house.

She watches him bury his… her… their mother and siblings beneath snow and dirt. An instinct recognizes blood and flesh. Floating, murky memories recognize family. She feels emptiness, though not hunger.

Tanjiro-nii takes her hand again. She treads after him in the snow almost passively.

A flash of memory, much softer than the others, reminds her that he has never minded leading.

She lets him guide her down the mountain.

* * *

Nezuko hates sunlight. She can think at least well enough to know _that_.

Even in the small cave, the warm rays make her skin prickle beneath her kimono. Another instinct, different from the one that still nags at her to eat, warns her away from the daylight. She burrows a hole and waits in the cool earth for Tanjiro-nii.

"She's gone!"

Nezuko pokes her head up and hums, malcontent. Her big brother blinks. He looks at her sympathetically.

"Really don't like the sun, huh?"

She hisses softly.

Tanjiro-nii spends the morning weaving a large basket. He doubles the layers, and binds the threads tight. Nezuko stays crouched in her hole. She only peeks out when her brother calls her name again.

"Can you get inside the basket?"

She hums. The basket looks a little like her burrow turned sideways. She crawls out of her hole. She pushes her head and shoulders through and flops when she cannot go any further.

Tanjiro-nii tuts.

"Nezuko," he says. "Remember before, when you made yourself bigger? Do you think you can make yourself smaller?"

Nezuko blinks a few times. Details are still hard to remember.

She does figure out that Tanjiro-nii needs her to _fit _in the basket, though. At his gentle prompting, she flips the basket upright and wriggles down.

She pops her head up, shrunken and swimming in her now too-large kimono.

Nezuko smiles a little with her eyes at the impressed sound Tanjiro-nii makes.

* * *

The day passes. Nezuko huddles in a place between wariness of the sunlight and comfort from the steady rhythm of Tanjiro-nii's feet. She's neither dozing nor fully alert in the protective cocoon of straw.

He lets her out after nightfall. They walk hand-in-hand together, further away from what's familiar. Nezuko can't say exactly what feels new or different from before, except that they are not home.

Tanjiro-nii remains, though, a constant at her side and always familiar. He talks with her as they walk, and though she cannot articulate answers, she listens. She feels the direction of his words more than she truly comprehends them- the lingering murk in her mind does not permit anything more defined.

She can sense his steady determination and attention to her, though, and that is enough.

When Tanjiro-nii gestures toward a light in the darkness, however, something in his face changes, and Nezuko feels his apprehension. He wrinkles his nose, and she remembers his acute senses, more potent than any wolf.

Even as a demon, his nose outstrips hers.

As they race up stairs toward the soft light, a buzzing sounds in the back of her mind. Sneaky and gradually stronger until they stand in the entryway of a temple and…

She loses track of Tanjiro-nii's presence.

A growl, an impact beside her, yet Nezuko cannot move. Humans, broken, clawed and bleeding all over lay scattered inside, mere paces away from her. The ache she has been ignoring readily all day returns. Nothing so sharp as before, as she isn't injured at all.

Only an… absence of fullness. _Empty_, that's what she feels, a physical emptiness that makes the flesh and blood before her an almost sensuous sight. Her instincts whisper to her, and she feels chilly, yet sweaty. Drool pools inside her mouth and oozes down her chin, dripping onto wooden floorboards.

_Satisfaction_.

Something promises her.

_Fullness, completion._

Her vision blurs a bit, eyes boring intently into the crimson, the warmth, the _blood_.

She remains rooted to the spot, an echo of a memory chafing at her singular desire- one telling her she shouldn't. That she would _never_.

Yet-

_'Smells… so… good.'_

Her tongue moves to moisten dry lips- the bamboo in her mouth blocks the way.

She can't- she won't, the echo says- eat them, but if she took the bamboo out. If she took a breath through her lips, she could taste the scent more intimately.

The echo sounds quieter, and she cannot remember who the voice belonged to in the first-

A choked shout snaps through the still night air like a whip.

_'!'_

Nezuko's vision sharpens. Her pupils slit. Her watering mouth dries up and her muscles coil. Ache entirely dismissed, she tears back out of the temple and across the stone path.

A demon holds Tanjiro-nii prone on the ground. Only a hatchet separates him from her brother.

Instinct, and an anger that belongs solely to Nezuko, intersect at the exact moment she strikes.

_'Kill!'_

The demon has barely glanced up before she smashes her foot into his head and kicks it from his body all at once. The head slams into a tree trunk and falls to the ground.

The body slumps. Tanjiro-nii looks up at Nezuko from the ground, shocked.

She frowns- she knows, inherently, that the demon has not been killed. A clawed hand reaches for Tanjiro-nii. She lashes out and sends the body into another tree with another kick.

The head speaks to her big brother- Nezuko doesn't bother to focus on his words. They remain an indistinct buzzing to her as she concentrates on the demon's headless body.

She moves when the body attacks her, but she struggles to fight. The demon has not been ignoring his hunger like she has. He moves more naturally than she can and she's soon thrown into the forest, away from her brother.

"Nezuko!"

Tanjiro-nii does not let the demon's head keep him from finding her. Though he's human and far more fragile, her big brother doesn't hesitate to tackle the demon right over the edge of a cliff.

She snaps her hand out and snatches the collar of his haori. She hauls him back up, and only his visible fear keeps her from getting upset.

She watches him passively while he pulls out a knife after they return to the temple. The demon's head, stuck to a tree by Tanjiro-nii's hatchet, hangs quietly. Her brother's chest heaves with every breath- yet the danger has passed, and she does not worry. Instead she stands guard in case the demon tries to break free.

The old man in a red mask surprises both of them. He _feels_ like Steel, only he does not make Nezuko's instincts scream danger in the same way.

She's not surprised at Tanjiro-nii's hesitation, before or after he picks up the rock.

Her brother has always been naturally gentle and kind.

The demon wakes up. Tanjiro-nii jumps. The head curses at him.

The rock rises over the demon's head. Stills. Hangs in the air.

The prickle of sunlight stings Nezuko's skin.

She lingers only long enough to hear the demon's first scream before she flees into the shadowed interior of the temple.

She drags her basket into the corner furthest away from the open entrance. She shrinks and huddles inside of it, white blanket draped over her head.

She stays awake until Tanjiro-nii finds her.

She's asleep well before they set off again.


	3. Chapter 3

A/N: Once again, let's see the world as Nezuko does. *Bows*

* * *

Waking up the third time… takes longer.

Much longer.

Nezuko does not quite dream. Instead, she wades, sifting through the bog in her mind. Intermittently, a voice speaks to her, acts as a guide. She does not recognize the speaker, nor can she make out the words clearly, only their intentions, giving her a direction.

Her guide does not always give direction- he disappears for long stretches, leaving her to wander. The direction is consistent, though, the bog shallower the further she goes. Memories come to her more easily, the echoes of her family closer to hand.

When she _does _wake, there's a distinct lack of Tanjiro-nii. His presence, his footsteps, even his scent are absent. She tosses off the bed roll and walks to the door, ignoring the presence of an older, not-Tanjiro as she goes.

She ignores the door, too, kicking it off the frame.

She has a brother to find.

"Nezuko!"

It's refreshingly easy.

Tanjiro-nii drops his crutch as he runs downhill toward her. Not a wise choice- at a glance, he's injured, dirty, and exuding deep weariness. Nezuko's not surprised that he trips at the foot of the slope and falls to his knees.

She makes up the distance for him, catching his head and cradling it to her shoulder. She can sense her big brother's aches, hear his relief through his sobbing. The embrace tastes like reunion, warmth at the end of an unyielding trek through the snow.

Nezuko knows he must have been at her side, but she missed him regardless.

She won't leave Tanjiro-nii alone again.

* * *

She spends more time dozing than sleeping. With no pressing need for recovery, Nezuko prefers to remain at least somewhat aware around Tanjiro-nii. She doesn't do much beyond listen to him, cozy under the bed roll while he tells her what he did while she slept.

She loves it.

The sun has risen and fallen many times when an odd man comes around. The bundle he carries holds a weapon- steel, she recognizes, passing hands to Tanjiro-nii.

A moment. Quiet.

Nezuko's nose prickles, her skin hums- the sword changes. Less like steel, it reminds her of Steel, how his weapon carried a promise of pain.

Her gentle brother wields it, though, and so she is not afraid.

A crow comes to call on Tanjiro-nii, cawing at him, and though her attention on the order wavers, she understands the flow of the words.

Demons. Girls. Disappearing.

They will leave soon, she knows.

* * *

Tanjiro-nii looks older, she realizes. Nezuko understands that, distantly, a quiet fact in her mind.

Donning the black uniform beneath his checkered haori, though, she sees him anew. All of her brother's stories about practice and work, the new scar on his face-

He's grown.

Tanjiro-nii shows her a new box to rest in- the old man's parting gift to keep her out of the sun. She shrinks and crawls inside, huddling her knees up to her chin comfortably.

Nezuko says her silent goodbyes to the old man in tandem with Tanjiro-nii. Back to back with her brother, she sleeps.

* * *

The sound of battle does not wake her.

Instead, Nezuko rouses at the sensation of Tanjiro-nii's fury, tight and tangible just behind her. Her own agitation rises in kind. She waits, coiled and ready, tracking the enemy until they make to strike at her brother's back.

She snaps out her leg and catches the demon's chin sideways. He flies back, neck twisted, and crumples on the ground.

Nezuko steps out of the box, alert- she knows the demon has not been killed. His presence is a vacuum, opposite to her brother.

The demon retreats, but does not leave. She turns to the other humans there. Gently, she cradles their faces.

An echo of her guide tells her

_Family._

The chill preceding a demon reaches her and she turns back. Pupils slit, fingers curled, claws bare, she charges, the same echo speaking to her.

_Enemy._


End file.
